1. Field of the Invention
The present invention relates to a driver element to be mounted on a display device such as a liquid crystal display device, and a display device having the driver element mounted thereon.
2. Discussion of Background
A liquid crystal display device or an organic EL (Electro Luminescence) display device is provided with a display portion in a display panel and a driver element (hereinafter referred to as a driving IC) to supply driving signals to the display portion.
As a system to connect the display portion and the driving IC, a COG (Chip On Glass) system is widely used. In the COG system, a method is commonly used wherein bumps (bump electrodes) formed on a mounting surface i.e. a surface on the side to be mounted on a glass substrate in the driving IC, are connected to electrode pads formed on the glass substrate, via a conductive material such as an anisotropically conductive film.
As shown in FIG. 9(A), in a driving IC 130 wherein the front and rear surfaces are usually formed rectangular as mounting surfaces, bumps 140 are arrayed in line along a long side on the front surface (mounting surface) (e.g. Patent Documents 1 and 2). Further, for the purpose of e.g. increasing the number of terminals without increasing the size of the driving IC 130, as shown in FIG. 9(B), a structure is also adopted wherein bumps 140 are arranged in a zigzag (or staggering) fashion (e.g. Patent Documents 1 and 2). Here, in FIGS. 9(A) and (B), bumps 140 are output terminals to output driving signals to drive the display portion, and bumps 150 are input terminals to input image signals, etc. from the side of the control device, to output image signals.
In the glass substrate on which a display portion and a driving IC are mounted, the area of a non-display portion should better be small. Accordingly, it is preferred that the driving IC is mounted close to the display portion.    Patent Document 1: JP-A-2009-99830 (FIGS. 1 and 4)    Patent Document 2: JP-A-2000-155330 (FIGS. 1 and 7)